With his pink shirt, gold ring, and posh accent, John Weguelin seems as if he’s been sent over by central casting to play the role of a London investment banker. And the room where he sits—with its carpeted hush, pale polished woods, and floor-to-ceiling windows overlooking a bustling street in London’s financial district—is blandly elegant, exactly what you might expect from a banker’s office. But neither Weguelin nor the European Islamic Investment Bank are exactly what you might expect. As managing director of E.I.I.B., the West’s first investment bank to comply with sharia, Weguelin is a central player in Islamic finance’s transformation from exotic niche market to mainstream investment.

A 30-year banking veteran whose résumé includes two decades at Bank of America, Weguelin was recruited two years ago by E.I.I.B. chairman Adnan Ahmed Yousif in 2005. Though Weguelin had no experience in Islamic banking—or even extensive experience in the the Middle East—he found the project too exciting to turn down. “The opportunity to establish a bank?” he grins. “How often in your working life does that come along?”

Not often, particularly when the job involves heading up Europe’s first independent Islamic investment bank. Though established in 2005, the E.I.I.B. received authorization from Britain’s banking regulators last March and floated on the London Stock Exchange with a £75 million initial public offering a couple of months after that.

Deft steering was required during last spring’s I.P.O., since it came at a moment when Middle Eastern equity markets were correcting by about 50 percent. “It took a bit of the gloss off everything that had been achieved,” concedes Weguelin who watch as E.I.I.B.’s stock went from 25 pence to half that within the week. The stock’s continued to sink, but Weguelin insists that the core busines is “sound.” Over a year on, the bank already has a market cap of $380 million, and a client base of sophisticated asset managers, hedge funds, and private banks buying for investors. In September, E.I.I.B. will launch a private equity fund with assets under management of about $125 million.

So far, so traditional. But for a clear sign of what makes E.I.I.B. different, just turn to the bank’s first annual report, in which briefings from the chairman and company secretary open with “In the Name of Allah, the Most Gracious, the Most Merciful” and calculations of shareholders’ zakah, an annual charitable donation required of all Muslims, are supplied. The cornerstone of the bank’s Islamic nature lies in its transactions and ventures, which are guarded by its Sharia Board—four Islamic scholars who vet funds and deals to make sure they don’t contravene Koranic bans on earning interest and making profit from alcohol, pork, or unethical activities. Before the bank undertakes a new investment, emails between the sharia scholars and the London office fly, allowing for what Weguelin says are ultimately “very relaxed” meetings that occur once every six weeks. “We’ve got one of the strongest sharia supervisory boards in the business,” says Weguelin.